Matt Murrow saw an ugly side to Blue Valley West High School in Overland Park, Kansas--teen drinking, threats of violence, and a student cussing at him still rattle in his memories. But the school resource officer took notice of those activities through an investigative tool some students would prefer he have no access to.

Facebook, MySpace, and Xanga--social networking web sites that students frequent--have garnered much attention as schools struggle with how to create policies addressing their use (see story: Social-networking sites confound schools). But the sites also have become a relatively new frontier that school resource officers are hunting through to find information on student crimes.

School resource officers, many of whom are city police officers stationed at the schools, say that tips on crimes can sometimes be gleaned from photos and content on social networking web sites. In some cases, students have been investigated and arrested.

To what degree school resource officers will use the sites varies. Because of the large number of student accounts on social networking web sites, some officers do not perform routine sweeps, and only examine the sites when they receive tips that pertain to them.

But for Murrow, who ended his term as a school resource officer at Blue Valley West last school year, routinely monitoring social networking web sites proved to be an effective tool at preventing and investigating student crimes.

To Murrow, the sites are fraught with illegal activity. During the three years he used the web sites, Murrow estimated there were about 40 incidents in which he confronted a student or parent about online activity that might have been crime-related.

Currently a patrol officer, Murrow said he began looking at the sites about three school years ago, when students had informed him about threats being exchanged online. Aside from the threats, the crimes included students posting information about teen drinking, drug use, and vandalism.

One such incident included a drinking party that 48 Blue Valley West students had attended. Murrow discovered it when pictures of the party were posted on a web site. He later informed a parent of the student who held the party, only to learn that the same student had created a new web site that criticized Murrow with swear words for using students' personal sites to investigate crimes.

Murrow's investigations also have spanned out of state into Indiana--where posted photos showed students vandalizing a veteran's lodge--and to the private school St. Thomas Aquinas, when a picture on a Facebook account showed a student there holding a martini glass.

He could not gather enough evidence to establish probable cause in certain cases, despite having found pictures online that suggested a crime being committed.